Worldwide, oil and gas companies spend more than $40 billion annually dealing with produced water from wells. The global direct costs from hauling water for treatment off-site alone will surpass $20 billion in 2007, with expenses skyrocketing in the next few years.
The US Department of Energy (DOE) has called produced water “by far the largest single volume byproduct or waste stream associated with oil and gas production.” The DOE further terms its treatment a serious environmental concern and a significantly growing expense to oil and gas producers.
In 2007, the world's oil and gas fields will produce over 80 billion barrels of water needing processing. The average is now almost nine barrels of produced water for each barrel of oil extracted. And the ratio of water to hydrocarbons increases over time as wells become older. That means less oil or gas and more contaminated water as we attempt to meet rising global energy needs.
By way of example, in rotary drilling a by-product of the drilling process is a waste fluid commonly referred to as “drilling fluids” which carries cuttings and other contaminants up through the annulus. The drilling fluid reduces friction between the drilling bit and the sides of the drilling hole; and further creates stability on the side walls of an uncased drilling hole. The drilling fluid may include various constituents that are capable of creating a filter cake capable of sealing cracks, holes, and pores along the side wall to prevent unwanted intrusion from the side wall into the drilled shaft opening. Water based drilling fluid's result in solid particles that are suspended in the water that makes up the fluid characteristics of the drilling fluid. Drilling fluid's can be conditioned to address various processes that may include water soluble polymers that are synthesized or naturally occurring to try to be capable of controlling the viscosity of the drilling fluid. The drilling fluid principle is used to carry cuttings from beneath the drilling bit, cool and clean the drill bit, reducing friction between the drill string and the sides of the drill hole and finally maintains the stability of an uncased section of the uncased hole.
Of particular interest in this example of a drilling fluid is the commonly referred to 9 lb drilling mud. Once this fluid is expelled, for purposes of on-site discharge the specific gravity of water separated need to be about 8.34 lbs per gallon to meet environmental discharge levels. One commonly known process is to use a centrifuge which is capable of lowering the 9 pound drilling mud to approximately 8.5 pounds per gallon. However, this level is unacceptable for environmental discharge limit and it would then be necessary to induce chemical polymers to flocculate the slurry and further treat the volatile organic compounds (VOC's) which are emitted as gases from certain solids or liquids. The VOC's are known to include a variety of chemicals some of which may have short or long term adverse health effects and is considered an unacceptable environmental discharge contaminant. Unfortunately, the use of polymers and a settling time is so expensive that it economically it becomes more conducive to treat the waste off-site which further adds to the cost of production by requiring off-site transport/treatment or shipped to a hazardous waste facility where no treatment is performed.
Thus, what is need in the industry is a reclamation process for reducing the need to treat industrial waste off-site and further provide an on-site treatment process for use in reclaiming water.
In addition there are many gas fields, most notably in North America, that contain enormous amounts of natural gas. This gas is trapped in shale formations that require stimulating the well using a process known as fracturing or fracing. The fracing process uses large amounts of water and large amounts of particulate fracing material (frac sands) to enable extraction of the gas from the shale formations. After the well site has been stimulated the water pumped into the well during the fracing process is removed. The water removed from the well is referred to as flowback fluid or frac water. A typical fracing process uses from one to four million gallons of water to fracture the formations of a single well. Water is an important natural resource that needs to be conserved wherever possible. One way to conserve water is to clean and recycle this flowback or frac water. The recycling of frac water has the added benefit of reducing waste product, namely the flowback fluid, which will need to be properly disposed. On site processing equipment, at the well, is the most cost effective and environmentally friendly way of recycling this natural resource.
It takes approximately 4.5 million gallons of fresh water to fracture a horizontal well. This water may be available from local streams and ponds, or purchased from a municipal water utility. This water must be trucked to the well site by tanker trucks, which carry roughly five thousand gallons per trip. During flowback operations, approximately 300 tanker trucks are used to carry away more than one million gallons of flowback water per well for offsite disposal. For a 3 well frac site these numbers will increase by a factor of three.
The present invention provides a cost-effective onsite water recycling service that eliminates the need to truck flowback to a disposal pit, a holding pond, or recycling facility miles away.